In recent years, a wearable terminal has been actively developed as information processing devices used while being worn on the user's body. Various kinds of wearable terminals having a shape similar to that of a gadget that is typically attached to the user's body, such as wristwatch or eyeglasses types, are developed, which are intended for using them while being worn on the user in daily lives.
In terms of the purpose of use, it is desirable to provide a compact and lightweight wearable terminal to reduce the user's fatigue or load that is applied during wearing it. An eyeglasses type wearable terminal (a kind of head-mounted display (HMD) or the like) is worn on the user's head, and thus, in particular, there is a great demand from the viewpoint of getting a better sense of fit. However, the wearable terminal is necessary to be equipped with a battery having relative large capacity for long-term use, which unfortunately leads to an increase in size and weight of a housing of the battery.
Therefore, various techniques are developed to reduce power consumption in a wearable terminal. As one example, Patent Literature 1 discloses an eyeglass head mounted display device that is equipped with an earphone and causes an image to be displayed on the lens portion of the eyeglass. This eyeglass head mounted display device detects whether the earphone are attached to or detached from the user's ear and controls display of an image on the basis of a result obtained by the detection.